This research is part of continuing study of the ethology of digger wasps of the subfamily Philanthinae (Hymenoptera, Sphecidae). At the present time major effort is being directed toward study of mating strategies in the genus Philanthus. There are five species of this genus in Jackson Hole (Evans, 1970). Two of these are more common elsewhere and are being studied elsewhere. Preliminary studies on the remaining three in 1977 revealed striking differences between the three and in one case a mating system unique among digger wasps (Evans & O'Neill, 1978). During late June and the first half of July, 1978, we made an effort to further confirm this unique system in P. zebratus and to obtain further data on P. pulcher, a very common early summer species in Jackson Hole. These efforts were successful, but P. pulcher also proved unique in some respects and we hope to continue studies of this species in the future. Other species of Philanthus are being studied elsewhere by our group, and we hope to include all of these comparative data in a behavioral monograph on the Philanthinae.